Q 1230201112.     wo adiabatic vessels, each containing the same mass ‘m’ of water but at different temperatures, are connected by a rod of length L, cross - section A, and thermal conductivity K. Ends of the rod are inserted into the vessels, while the rest of the rod is insulated so that there is no loss of heat into the atmosphere. Specific heat capacity of water is ‘s’ , while that of the rod is negligible. Temperature difference between the two vessels reduces to `1/e` of its original value after a time Δt. Thermal conductivity (K) of the rod may be expressed by